Advice re: lyophilizers requested

I would appreciate some advice about purchasing a lyophilizer. I will have
relatively small volumes (<2L/day), but substantial amounts of acetonitrile
in those volumes. Clearly, I must either use some kind of pump which is
impervious to acetonitrile, or take special precautions to protect the pump.
Specs for a Labconco lyophilizer indicate that it will refridgerate to -65C,
undoubtedly not cold enough for a substance which, when pure, melts at -45C.
Labconco has a 2-stage model which refridgerates to -112C. Cost is about
$8000, compared to about $4000 for the -65C model.
My questions are:
1. Is -112C cold enough to protect common pumps from acetonitrile?
2. Are there other lyophilizers out there which would be better?
3. Is it all-around best toset up a secondary trap on a -65C machine and
feed it -196C liquid nitrogen as needed?
4. Is there a better type of pump to use?
Thank you,
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--------------------- axe at pharm.med.upenn.edu --------------------------------
Paul H. Axelsen MD .... .... . . . . 215-898-9238 (ofc)
Department of Pharmacology . . . .. . .. . 215-898-9766 (lab)
University of Pennsylvania .... ... . . . . . . 215-573-2236 (fax)
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